<!DOCTYPE html>
<html lang="zh-CN">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <script src="/Public/js/three.min.js"></script>
    <script src="/Public/js/OrbitControls.js"></script>
    <script src="/Public/js/jquery-3.7.1.min.js"></script>
    <script src="/Public/js/geotiff.js"></script>
    <script src="/Public/js/f3d.js"></script>
    <style>
        body {
            margin: 0;
            overflow: hidden;
            background: #1a1a2e;
            font-family: Arial, sans-serif;
        }
    </style>

</head>

<body>
    <script>
        let terrainMesh = null;
        let heightScale = 0.5;
        let smoothness = 3;

        const scene = new THREE.Scene();
        scene.background = new THREE.Color(0x1a1a2e);

        // 创建相机
        const camera = new THREE.PerspectiveCamera(60, window.innerWidth / window.innerHeight, 0.1, 10000);
        camera.position.set(1, 50, 3);

        // 创建渲染器
        const renderer = new THREE.WebGLRenderer({ antialias: true });
        renderer.setSize(window.innerWidth, window.innerHeight);
        document.body.appendChild(renderer.domElement);

        // 添加光源
        const ambientLight = new THREE.AmbientLight(0x404040);
        scene.add(ambientLight);
        const directionalLight = new THREE.DirectionalLight(0xffffff, 0.8);
        directionalLight.position.set(1, 1, 1);
        scene.add(directionalLight);
        // 添加控制器
        const controls = new THREE.OrbitControls(camera, renderer.domElement);
        controls.enableDamping = true;


        const plane_geometry = new THREE.PlaneGeometry(5, 5)

        const vs1 = `
            varying vec2 vUv;
            void main() {
                vUv = uv;
                gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);
            }
        `;

        const fs1 = `
            varying vec2 vUv;
            uniform float time;
            void main() {
                if(vUv.y < fract(time)) {
                    gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
                } else {
                    gl_FragColor = vec4(0.0, 1.0, 0.0, 1.0);;
                }
            }
        `;

        const fs2 = `
            varying vec2 vUv;
            uniform float time;
            void main() {
                if(vUv.y < fract(time + 0.1) && vUv.y > fract(time)) {
                    gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
                } else {
                    gl_FragColor = vec4(0.0, 1.0, 0.0, 1.0);;
                }
            }
        `;

        const fs3 = `
            varying vec2 vUv;
            uniform float time;

            void main() {
                float t = fract(time);
                float bandWidth = 0.1;
                
                // 处理边界情况
                float inBand;
                if (t + bandWidth <= 1.0) {
                    inBand = step(t, vUv.y) * step(vUv.y, t + bandWidth);
                } else {
                    inBand = step(t, vUv.y) + step(vUv.y, t + bandWidth - 1.0);
                }
                
                vec3 color = mix(vec3(0.0, 1.0, 0.0), vec3(1.0, 0.0, 0.0), inBand);
                gl_FragColor = vec4(color, 1.0);
            }
        `;

        const material = new THREE.ShaderMaterial({
            vertexShader: vs1,
            fragmentShader: fs3,
            uniforms: {
                time: { value: 0.0 }
            },
            transparent: true,
        });

        const plane = new THREE.Mesh(plane_geometry, material)
        plane.position.set(0, 20, 0)

        scene.add(plane)



        // 动画循环
        function animate() {
            requestAnimationFrame(animate);
            material.uniforms.time.value += 0.001;
            controls.update();
            renderer.render(scene, camera);
        }
        animate();


    </script>
</body>

</html>